Ballistic articles including body armor such as bullet proof vests are known. Body armor including layers of fabric made from woven high strength plastic fibers is also known.
There are at least three desirable characteristics associated with body armor. First, body armor must prevent penetration by an incoming high energy projectile. Second, body armor must minimize the impact of an incoming high energy projectile. Minimizing impact is determined by evaluating the back face deformation which corresponds to trauma level experienced by a projectile that does not penetrate the body armor. This also refers to blunt trauma, which corresponds to the amount of energy transferred to a user of body armor upon impact of a high energy projectile. Finally, body armor must be comfortable enough in order to induce increased use. There are, in turn, three key factors which affect the comfortability of a given body armor; namely, weight, thickness and flexibility.
Ballistic vests are regularly certified by subjecting them to ballistics testing to measure there ability to protect against different projectiles fired from different types of weapons at various angles. One ballistic test commonly used in the industry is the National Institution of Justice (NIJ) Standard 0101.03. NIJ Standards establish minimum performance requirements and methods to test body armor for ballistic resistance. In particular, the Standard sets minimum levels of a number of characteristics including performance in connection with preventing penetration and minimizing backface deformation.
In particular, ballistic tests are provided to address many different projectiles and energy levels. Three of these tests include NIJ Threat Level II, IIA and IIIA. Threat Level II relates to higher velocity 357 magnum (158 gr) and 9 mm (124 gr) bullets (impact velocities of less than about 1395 feet per second and 1175 feet per second, respectively). Threat Level IIA relates to lower velocity 357 magnum (158 gr) and 9 mm (124 gr) bullets (impact velocities of less than about 1250 feet per second and 1090 feet per second, respectively). Threat Level IIIA relates to 44 magnum (240 gr) and submachine gun 9 mm (124 gr) bullets (impact velocities of less than about 1400 feet per second).
Generally speaking, providing body armor which effectively prevents projectile penetration and minimizes backface deformation is uncomfortable. Similarly, body armor which is comfortable has undesirably low levels of projectile penetration and backface deformation. Although ballistic performance appears inversely proportional to comfort, there is a need to provide body armor which possesses simultaneously the ability to prevent penetration of projectiles, minimize backface deformation and provide increased comfortability. In other words, there is a need for body armor of increasingly lighter weight, decreased thickness while preventing penetration by incoming projectiles and minimizing blunt trauma.